The semiconductor industry is continuously moving toward the fabrication of smaller and more complex microelectronic components with higher performance. Market pressures are driving the industry to produce smaller components, but there is also significant market pressure to reduce costs while making smaller components. There are numerous steps in the manufacture of many integrated circuits, and each step has an associated cost. New methods that eliminate manufacturing steps generally decrease the cost of production, and can also increase the speed of manufacture.
Many integrated circuits include memory cells to store information, and the memory cells are becoming smaller and more complex with the rest of the microelectronic components. There are several different types of memory cells, including flash memory that is non-volatile and re-writable. Non-volatile memory retains stored information even when the memory cell is de-powered, and stored information can be changed when a memory cell is re-writable. Some memory cells for flash memory store information by either charging or draining an electrically isolated component, and the information is recalled by determining if the isolated component is charged or not. One type of memory cell used for flash memory is a thin film storage cell that uses discrete storage crystals, called silicon nanocrystals, to hold the charge. The storage crystals are relatively small, so thin film storage cells are useful for reducing the size of memory cells. One type of memory cell structure using thin film technology is a 1.5 T split-gate cell with a spacer control gate, where one drain is shared with two select gates, and one source is shared with two spacer control gates. These memory cells are typically produced by first manufacturing arrays of select gate transistors, and then forming spacer control gates adjacent to the select gates; thus forming the 1.5 T split gate structure. The process for forming the select gates also produces shoulders in between the control gates overlying the drain, and the shoulders are removed by applying a mask to protect the select gates and using a highly selective etch step to remove the unwanted spacers.
Accordingly, it is desirable to provide methods for producing a memory cell with fewer manufacturing steps. In addition, it is desirable to provide methods for producing a thin film storage memory cell using simplified processes to reduce the complexity of the manufacturing steps involved. Furthermore, other desirable features and characteristics of the present embodiment will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.